An engineered selenocysteine defines a unique class of antibody derivatives
An engineered selenocysteine defines a unique class of antibody derivatives
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DOI：
10.1073/pnas.0800800105
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发表时间：
2008-08-26
影响因子：
11.1
通讯作者：
Rader, Christoph
中科院分区：
文献类型：
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作者：
Hofer, Thomas;Thomas, Joshua D.;Rader, Christoph
通过重新编码从终止到硒代半胱氨酸插入的终止密码子 UGA，硒代半胱氨酸被共翻译插入到蛋白质中。硒代半胱氨酸的亲核硒醇基团赋予这种稀有氨基酸独特的化学反应性，允许在其他天然氨基酸存在的情况下进行区域特异性共价缀合。使用哺乳动物表达系统，我们生成了具有 C 端硒代半胱氨酸的 IgG1 衍生 Fc 片段，其产量与传统单克隆抗体相当，并将其与肽模拟物的亲电子衍生物缀合，该衍生物以高亲和力和特异性与整合素 α(4)β(1) 结合。通过这种结合，生物和化学成分都被赋予了药理优势。我们证明，虽然 Fc 蛋白将循环半衰期从几分钟延长到几天，并通过与新生儿 Fc 受体结合介导转胞吞作用，但肽模拟物引入了与细胞表面整合素 α(4)β(1) 的跨物种结合，并阻断其与血管细胞粘附分子 1 的相互作用。与传统的单克隆抗体相比，我们的技术将通用生物成分与可变化学成分相结合，从而在经济上受益。
Selenocysteine is cotranslationally inserted into proteins by recoding the stop codon UGA from termination to selenocysteine insertion. The nucleophilic selenol group of selenocysteine endows this rare amino acid with unique chemical reactivity that allows regio-specific covalent conjugation in the presence of the other natural amino acids. Using a mammalian expression system, we generated an IgG1-derived Fc fragment with a C-terminal selenocysteine in yields comparable to conventional monoclonal antibodies and conjugated it to an electrophilic derivative of a peptidomimetic that binds with high affinity and specificity to integrin alpha(4)beta(1). Through this conjugation, both the biological and chemical components are endowed with pharmacological advantages. We demonstrate that whereas the Fc protein increases the circulatory half-life from minutes to days and mediates transcytosis through binding to the neonatal Fc receptor, the peptidomimetic introduces cross-species binding to cell surface integrin alpha(4)beta(1) and blocks its interaction with vascular cell adhesion molecule-1. Compared with conventional monoclonal antibodies, our technology benefits economically from combining a generic biological component with a variable chemical component.